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Internal auditory meatus

Bone: Internal auditory meatus
Left temporal bone. Inner surface.
Diagrammatic view of the fundus of the right internal acoustic meatus.
Latin meatus acusticus internus
Gray's subject #34 143

The internal auditory meatus (also internal acoustic meatus, internal auditory canal, and internal acoustic canal) is a canal in the petrous part of the temporal bone of the skull that carries nerves from inside the cranium towards the middle and inner ear compartments namely cranial nerve VII and cranial nerve VIII.

Structure

The opening to the internal acoustic meatus is located inside the cranial cavity, near the center of the posterior surface of the petrous bone. The size varies considerably; its margins are smooth and rounded. The canal is short (about 1 cm) and runs laterally into the bone. At its end are the openings for three different canals, one of which is the facial canal.

The internal acoustic meatus transmits the facial and vestibulocochlear nerves and the labyrinthine artery (an internal auditory branch of the basilar artery). The facial nerve travels through the facial canal, eventually exiting the skull at the stylomastoid foramen.

The opening of the meatus is called the porus acusticus internus, or its English translation, the internal acoustic opening.

The antero-superior part transmits the facial nerve and nervus intermedius and is separated from the postero-superior section, which transmits the superior vestibular nerve, by Bill's bar (named by William House who founded the House Ear Institute). The falciform, or transverse, crest separates the superior part from the inferior part. The cochlear nerve runs antero-inferiorly and the inferior vestibular nerve runs postero-inferiorly.

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This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.

 

The content of this section is licensed under the GNU Free Documentation License (local copy). It uses material from the Wikipedia article "Internal auditory meatus" modified November 23, 2010 with previous authors listed in its history.